06 May, 2009

These past few weeks I've been thinking about multi-purpose bikes, like a city bike that would be comfortable and fast enough for a long ramble in the country. This is something I hope folks will do with our new Polyvalent (formerly city bike) frame. This in turn led to some thoughts about a suitable and inexpensive crank.

I've explained previously why I'm a big fan of wider range doubles, but here it is again. With modern 8, 9, 10, and even 11 speed cassettes there is simply no need for a middle ring. On a bike with a 46/30 or 48/30 rings and, say, a 12-28 cassette, you can motor along in a pace line at close to 30mph, though perhaps not for long. And you can probably climb most any paved road. Of course I'm not considering loaded touring bikes here.

With a 9-speed cassette you'll have a wide range of reasonably closely spaced ratios. I've found that the FSA, and Campy front derailleurs have no problem shifting from the big to the little ring, though front shifting is a little slower. Fortunately you'll find that you can stay in the big ring most of the time. It's only in the mountains that you use the front derailleur frequently.

The main problem with this setup is that the TA and Sugino PX cranks best suited for wide range double duty are rather expensive and may not be made again. In trying to come up with an economical solution we're messing around with a Sugino XD triple with a chain ring guard in the outer position, a 46t in the middle, and a 28t inner.

There are a couple of issues that keep this from being a perfect solution. The Q-factor for triples is rather wide, but I think most people make too big an issue of Q-factor. There is no question that a wide Q does bother some folks, but the majority of cyclists don't seem to care. The other issue is that 30t 74bcd rings are uncommon, as are 46t middle rings, but we can get some.

On the plus side this crank would probably sell for around $100. And the chain ring guard keeps your cuff clean.

If enough folks like this we can order stock cranks configured this way. Would you try them?

BTW, if you try this at home and don't have a 46t or 48t middle ring, you can possibly use an un-pinned outer ring in the middle position, but no guarantees. We're still playing around trying to find the best rings and BB length.

63 comments:

I don't know much about cranks as I've only ever used 39/53 doubles. But I have figured outsomething about keeping cuffs clean even on a derailleur'd setup.

The prototype alloy chainguard that VO very genteelly mailed to me in the fall has a notch for a front derailleur. It works perfectly and required no fiddling with the FD to make it clear. I think the bike in question just has a normal Campy Centaur non-CT derailleur.

If you want to keep cuffs really clean, the outer chainwheel ring does next to nothing because where your trousers rub against the chain is a couple/few inches aft of the chainring. You really have to use a regular chainguard if you wear seersucker suits and want to arrive spotless. It doesn't get in the way much. While I wouldn't put one on my racing bike f'chrissakes, I wouldn't be troubled having it on any other bike.

Dadgum, I wish I had thought of that. I ride a longtail, 14-25 in the rear, 26/36/46 in front, and I could just discard the 36. 26/14=1.84, 46/25=1.84. It's just sitting right there in the spreadsheet, duh.

And because it's a longtail (almost twice the distance from crank to axle) I can shift large/large and small/small without so much chain deflection.

I guess I need to look into a chain ring guard. That would be very nice, I'd have cleaner pants. Perhaps you could devise a partial chain case for such a beast? :-) If I could keep some of the front wheel slime out of the chain (winters are hard on chains).

This is a timely post for me as I was just setting off to research if something like this was possible. My wife's cyclocross bike with double chainring is geared too high for her, so rather than convert to a triple I was wondering if it is possible to just downsize both chainrings considerably. It is only a 7 speed in back, but for her the upper end isn't very important and she is not going to be found in a paceline anytime soon.

Yes, Shimano and others do make 30t 74bcd chain rings. I was looking at a couple of wholesale catalog and they don't have nearly as many options for them as 26t and 28t rings. So I was wondering if a many shops stock them. maybe they are more common than I thought.

I think the 46/30 chainring combination would be just about perfect for most general-purpose riding needs. Combined with a 11-28 cassette, it's high enough for flat road rides and low enough for hilly areas. The XD cranks are very good, in my opionion, and having the option for a double with a chainring guard would be great! Count me in if you decide to offer them.

I'd prefer to see the time, energy and money invested into a proper wide range double. There is really no gain with this proposed Sugino set-up vs. the standard Sugino triple - other than aesthetics. You could just as easily move the outside ring into the middle and forgo the chain guard ring - or just ride a triple and ignore the outer ring, which is what I do on several bikes. Plus, in my opinion, the proposed crank looks kludgy.It's almost criminal that nobody makes a wide range double - they just make too much sense. I've been looking forward to the VO wide range double that was hinted at a while back - I hope it eventually gets made!Gary

The VO 50.4 BCD crank is on hold until we find out if a certain crank manufacturer decides to make one. That may happen soon and we are on board to distribute them if it does. In that case it would be pointless to duplicate their efforts. The other possibility is to have one quickly made by a CNC shop in the US. That would be simpler and faster, but just as expensive as the TA.

I like the idea because it is simple, affordable and utilitarian. I would like this even more if you could get the old Sugino crown logo, which is better in so many ways. Can you convince them that for this market, it's a much better logo?

Jimmy D, brother you just missed out -- should have checked on the VO store just a few weeks ago: they'd had an italian BB up there like forever. a sweet-looking adjustable edco contraption too. bummer.

Chris, are there 46-48t 110 or 130 bcd chainguards out there that us consumers can get our hands on? This one of those parts I can't ever seem to find -- there are a million 42t carbon guards out there for cyclocross, and I once found an Al 42t 110, but if you don't end up doing this crank just selling these guards would be a boon to those of us who want wide but sane gearing.

Great idea - I run a Suntour Superbe road triple crank (130bcd) with a CNCed chainguard in place of the outer, a 39t middle ring and a 30t inner. Keeps my trouser cuff intact and gives me all the gears I need for commuting and loaded touring, on and off road. It's a killer setup and I don't know why more bikes are specced like this...

What about using a standard 130/74 triple crank and using 46x30 as middle and inner rings and simply using BMX or track chainring bolts? In other words, without the chainguard. Not pretty, but seems like it should work, no?

Don't bother having 50.4 arms CNC'd if they are the same as TA's.If the "big" company you mention doesn't do it, find somebody in Taiwan to make forged 50.4 arms (and inexpensive rings while they are at it). I know it's a big project with an extra helping of headache but it would be so worth it! So many of us want that crank - there is no way it wouldn't be a hit!Gary

Chris, 74bcd 30t rings are all over the place. Standard triple inner, and most shops have them in stock.

I'm partial to using 5x94BCD cranks as wide-range doubles. Pull off the 56 or 58bcd small ring, and go to a 30/44 or 30/46. Depending on the crank and method of attaching the small ring, Q can sometimes be reduced too.

There are a bunch of these cranks out there, but even without a small ring "Q" tends to be fairly wide. Consider this a vote for a proper 5x94 double.

30t 94bcd rings are available, but you don't have a bunch of choices(every shop I asked said no, but they had 30t 74bcd on hand). Still, for how often I replace rings, that's not really an issue.

Sean, the big advantage for me is it's easier to set up indexed shifting to work well on a double than a triple. Also, I use the 44t most of teh time, and only break out the 30t for hill climbing.

One disadvantage is that the 30t really only works with the largest 4 or 5 cogs on my cassette, otherwise the chain rubs on the big ring. This hasn't bothered me, as my shifting pattern tends to take me to the big ring before it's an issue.

I'm currently not in a position to buy a new crankset/bottom bracket combo and have a 130bcd road crank. I am currently running a single 44t chainring up front and want to go double on it.

I am considering a 48/38 combo on the front - I currently have a SRAM 12-34 cassette on the back. This will be used for mostly Ghettoneuring in the city, commuting and hopefully some slightly longer trips on the weekend - but that last one's not here yet for a few reasons.

What does the hivemind think about a 48/38 front combo with 12-34 in the back?

I took big ring off the 52/42/30 triple, replaced the 30 with a 26 from old mountain triple - same 74 bcd. Put close ratio 12-23 9 speed on back. I live in the hills and find the range adequate and love the close ratio. The advantages are the easier to set up 2 position front derailleur, plus superb shifting from a short cage rear derailleur ($40 ebay dura ace)

"White are highly durable and maintain their good looks for a long time. "Good looks are subjective - I find that WI crank to be real eyesore. I'd take a nice simple forged crank along the lines of a Sugino AT any day. Gotta have a true, 5 arm spider though - the 5th arm hidden behind the crankarm is a no-no.

How about a 86 pcd crankset - like the stronglight escape (escapade?) A double (or triple) that uses "normal" chainring bolts and takes rings down to 28T. Probably made in the far east these days (if at all). Reasonably priced custom chainrings are available from a number of sources if you're worried about long term support. CheersStevy

I've been running 44/30 TA rings on my Sugino triple for a while now. It's a great set-up for just about everything but loaded touring. I think just putting the outer ring in the middle ring position and skipping the chainguard looks a lot nicer.

Am I the only one in the world who likes triples? Big rings for tailwinds, downhills, and endorphin rushes. Small for the big climbs...lots around here. Middle for everything else. Chainguards??...just roll up the khakis.

I've been running a Cyclocross Compact (48-34) for a couple months now but I'm using an 11-32 cassette to take the hills. Once out of the hills I miss the tighter spacing of a typical road cassette. I "built" a 42-30 w/ chain guard using an old triple but not enough top end. I would love to have a 46-30 or 48-30 crank so I can switch back to the tighter spacing of my 12-26 cassette.

As usual, you're on target. A "usuable" double is light years past having a triple for utilitarian use. I can see the advantage of having your set-up and agree it would address all needs for speeds. However, I have a touring triple and am as happy as a pig (not the swine flu kind) with what I have. But, if I ever buy another bike or begin to worry about clean cuffs, I'll consider a double with no reservations.

The Stronglight linked above (by Uncle Ankle) would probably be great if it was polished instead of anodized. I'm sure most would object to the ISIS drive, but perhaps Stronglight could be convinced to make a small run of square tapers for this crowd?

I use Sugino PX cranks with TA 44 and 28 chainrings and an 11-34 (9 speed)cassette. This provides 9 clear speeds while on the 44, plenty of climbing power for nasty rural climbs and enough speed with 44X11 for dirt-roads and most solo riding. The 28 is sufficient bail-out gearing for the worst circumstances.

I have not been watching all these blog threads closely, but was under the impression that VO was looking at a new TA/Sugino PX style of crank. I would be interested in these and in ramped and pinned outer rings.

I do find the 28 to 44 shift requires a little vigilance. Ramped and pinned outer rings in the TA format would help, as would a purpose designed front derailleur cage.

There are enough nice looking 110/74 mountain triples out there, and a plethora of chainrings in those sizes, so how about just working on a nice looking chainguard. Something that looks a little more sleek and refined than the Sugino you already sell, something more like a chainring without teeth than a giant bashguard.

The AT that I referenced has no curves - dead straight arms! So there! ;)

Also, I like the suggestion a few comments above of just offering an elegant chain guard for the outer ring instead of this proposed Sugino double with that chunky bash guard. It would be much less expensive for folks to try out and most of us have an old triple in the parts bin. If not, they are easy to come by. 15 seconds of searching uncovered this:http://micurl.com/v20iftNot a bad start!

Guard was the first thing that caught my eye. Would defenitely buy this. Would preffer for it to look a look a little more retro. Perhaps something that would blend easily into a late 60's to early eighties rand/road bike.

i just added a 24 to my girlfriend's mountain crank, which was previously running a sole 42. I find the wide double to be more elegant than the triple, personally. unfortunately, she is not an extremely skilled rider and has trouble managing the large shift. someday.

That guard is too big. Perhaps a smaller one for people who wanted a guard.

Otherwise, what I'd thought to do was to cut off sections of the 53 tooth sprocket to act as the washers, and so that I could just use the regular lenght nuts/bolts. Then I'd have a 42 tooth single sprocket. If I wanted, I could add a 28t granny sprocket. This is to a Sugino XD double.

But, then, I've got a PX 42/28 and am blissfully happy. I don't have to look around for the middle sprocket while shifting. It's easy! It's light!

I must object to the idea that Q-factor is not significant. For the people who are sensitive to it, it can be quite a pain. I for one would have no use for a "Wide Double" as described.

The first time I rode a bike with a low-Q crank, (a vintage Fuji S10S), it was a revelation. Ever since, I'm well aware that my triple-equipped general rider is unsuited to my narrow-hipped anatomy, and I wish for a true (narrow) wide-range double most every ride.

So I'm saving my pennies till VO or another maker comes out with that crank. Till then I guess I'll just be hipped and cranky... ; )

One thing to keep in mind here is the application that Chris is primarily addressing - city bike, which in its full incarnation means upright riding, street clothes, short hop riding at moments notice with max convenience.

In that case, there is something to be said for a chain-guard rather than leg-band or trouser tuck. I think the Sugino chainguard is a little ungainly, but it has potential with some shine, engraving or other detailing.

Similarly, a double where the rider is almost always on the larger ring simplifies life a lot.

Other posters have pointed out various limitations of this configuration, but I think that this is a pretty good solution for the stated purpose. It certainly isn't being put forth as something one should use for all modes of riding.

Another competing solution for this scenario is a double with chainguard and internal gear hub rear. IMO, that is a lot better city bike configuration, but has the considerable downside of significantly greater cost.

I purchased one of the beautiful Sugino cranksets from you. 48-36-26 I would not trade my middle ring for a chain guard, and i'd rather have a 26 tooth granny ring than a 30. If i want a compact double I'd set up a 50-34 and use a wider cassette in back.

What 'wide/fat/ungainlyness' are you all speaking of with regards to the guard in the photo?

Cyclocross guards are generally a thinner aluminum sheet (1.5-3mm) and not at all like the 6-12mm thick bashguards used on DH bikes. The Sugino guard on that chainring is 1.5mm thick at the bolt tabs and the ring itself. You can't get any thinner than that without it being tin foil.

Also, we do sell the guard right now. There are 2 versions: 44-46 and 48-50t with a 110 bcd.

Speaking only for myself, the "bash guard" comment was more in line with the aesthetic than the application. It's not a terrible looking chainguard but it's nothing special either. Something more along the lines of a nice, open, lean and light chainring, minus the the teeth, would be most welcome. Look at the Zeus guard that I posted earlier, lose the drillium and make it about the size of a 40 tooth chainring, now we're talking. Oh yeah, make one closer to 46 as well for all the burly dudes. I guess I'm old and slow at the ripe age of 36 but I don't need anything larger than 36 up front with an 11 or 12 cog on the cassette (!)

Tom, I think what _might_ be turning people off to the guard in the photos is the photography. The flash seems to have diminished the appearance of any defining surface contours of the shape.

But for contrast, the steel Zeus guard mentioned above ( http://micurl.com/v20ift ) appears gossamer and finely detailed compared to the apparent amorphousness of the Sugino. A case perhaps where the stronger yet heavier metal is well employed.

You guys can continue the mental gymnastics about what is better. Me, I just ride, and I love my triple. I'm a just a small, upper middle-aged, and not totally healthy man, and I have to say, I use my 50 big ring quite regularly, on downhills, relative flats with tailwinds, etc. Surely, you big, strong guys must find a 46 somewhat limiting.

I use my middle 40 ring a lot, and I use the 30 inner ring when I'm climbing something without trying to set any records. In between those things, I really, and I mean really appreciate the close ratios. They allow me to keep my rides very finely tuned with almost no double shifting, and all this together helps me make the most of my limited abilities - either in relation to speed or endurance.

Just me, but I can't imagine why people who profess to be randonneuring types would scoff at triples.

This discussion got me thinking, and my will to tinker and mess things up began to take over as I was looking at a spare triple I had lying around. It seems it could be fairly easily modified to create a lower-Q wide double than the Sugino with guard...

You could first machine off the inner standoffs that space the granny away from the middle ring, so that the new mounting surface is flush with where the middle ring used to be. Then, if needed you could deepen and re-tap the granny mounting holes, but at least on the crank I was looking at, it seemed it would be ok as is. Then just mount the small ring as normal with spacers, and put a big ring outside...

Can anyone comment on whether this would work? Or would the reduction in Q be too slight to notice and too little for all the trouble?

Low Q double crank with a 5-arm 86 mm or 94 mm BCD would hit a ripe market. Rings are available, although a bit pricey.White Industries are on the right track with their VBC. TA Carmina is bloody expensive. Middleburn have a road version of their RS7 in the works, but have been very quiet about if for some 2 years now.

SAREN's idea of machining out a triple to turn it into a double is only a half-solution because:1. The Q-factor is unchanged (still a triple)2. The chainline is way off.This could be addressed by using a shorter BB, but then the clearance between crankarms and chaninstays may be compromised.All in all, too much hassle.

The suggested Oxale 2 of Stronglight's is a MTB triple, and as such has a very wide Q-factor. No BB could bring it to a road double chainline and/or Q-factor.

Glad to read your feedback, IK. Looks like there are some things about crank geometry that I need to understand better! I'll have to compare some cranks with different Q's so I can get the gist of what the differences really are...

I was recently thinking of doing exactly what you proposed in this posting. I have an XD triple 46/36/24and almost never use the middle ring. But as I thought about it and the ideal chainring potentials I got to thinking why nobody has thought of manufacturing a 110/74 double. This would seem a natural successor to those TA style cranks and allow for limitless gearing options, especially for those who don't fret about flawless shifting.

I've wanted a really nice 46/30 type double for ages. What I do, instead, is use a triple, but the outer and middle rings I leave very closely spaced--48/42 or such--and then use a 28 or 30 for the inner. That way I've got all sorts of options, and not trying to force a properly "triple" crank to be a double, just for the sake of it. Until there's a true 74 BCD double crankset on the market, I don't see the point of going to all the effort to turn a 110/74 into a wide-range double...

Coming a little late to this discussion, but why wouldn't an outer 46 work in the middle position, paired with an inner 28 or so?

And what do you think is the biggest reasonable drop assuming the use of a friction bar end shifter? Ideally I would probably run a 46 and 24, but that may be too much. On my tandem, I run a 24, 44, 54 triple (it's a road tandem with 26" wheels and 7 speed cassette, so the wide range is really welcome) and shifting from the 44 to the 24 works, but isn't great (chainrings are unpinned)

This combination is perfect. I've been using a 46/28 combination on my road bike for over a year now. My touring/commuting bike and my cyclocross bikes each have 42/26 combinations, all with 10-speed cassettes with either 11- or 12-tooth small cogs and 25- to 28-tooth large cogs. I like the name "super compact double" for these cranksets.

I use the inner and middle positions of a 74/130 triple cranksets for all of these, and only worry about a chainguard on the tourer/commuter. I'd love to get one or more reasonably priced double cranksets that can take these combinations. You talk about the possibility of a 74/110 double, but why not a 74/130 double? I can't imagine anyone needing smaller than a 38 tooth in the outer position, so why use a 110 BCD for this?

Any more news of the crankset shown in this blog posting:http://velo-orange.blogspot.com/2009/03/taipei-cycle-show-update-3.html